1. Field of the Invention
This invention relates to flow testing of wells and more particularly to test tools which are run on a flexible line and are operable thereby from the surface to shut-in a well and to open it up at a subsurface depth, especially at a location just above the formation being tested.
2. Description of the Prior Art
Until a few years ago, downhole well data were generally obtained by lowering a bottom hole pressure gage into a well on a wire line after the well had been closed in at the surface for maybe 48 to 72 hours. The gage usually carried a maximum-recording thermometer. The gage was lowered to a location a predetermined distance below sea level, usually at or near the casing perforations. The gage was usually suspended at this depth a few minutes while the well remained shut-in to record the formation pressure and temperature. The well was then placed on production at a predetermined rate of flow to obtain recordings of the draw-down characteristics of the well. The data thus obtained were then evaluated by reservoir technicians to aid them in their effort to determine more accurately the extent, shape, volume, and contents of the reservoir.
Since the well was controlled by valves located at the surface, usually a great distance from the reservoir, problems arose as a result of the reaction of the column of production fluids in the well tubing. During shut-in periods liquids would settle on bottom and the gas would collect thereabove, introducing uncertainties into the data obtained and clouding the formation's charasteristics. It became desirable to have the ability to open and close the well at a point as near the perforations or reservoir as possible and thus avoid the need to build up and draw down the great volume and height represented by the well bore or well tubing extending many thousands of feet from the reservoir to the surface. Further it was desirable to run a test tool including sensor means on a conductor cable and be able to control the downhole opening and closing means from the surface, and to record and display at the surface and in real time the downhole data as they were sensed by the test tool.
The applicants are familiar with the following prior patents which may have some bearing upon the well testing problems as relates to the present invention.
______________________________________ Re. 31,313 4,043,392 4,278,130 2,673,614 4,069,865 4,286,661 3,208,531 4,134,452 4,373,583 3,419,075 4,149,593 4,420,044 3,472,070 4,159,643 4,426,882 ______________________________________
Also, they are familiar with a brochure published by Flopetrol-Johnston covering their MUST Universal DST device.
Applicants are further familiar with an editorial comment published in WORLD OIL magazine, page 21, October 1983 Edition.
In addition, they are familiar with the landing nipple illustrated on pages 506 and 507 of the Composite Catalog of Oil Field Equipment and Services, 1970-71 Edition, published by WORLD OIL magazine.
U.S. Pat. No. 4,134,452, issued to George F. Kingelin on Jan. 16, 1979; U.S. Pat. No. 4,149,593, issued to Imre I. Gazda, et al, on April 17, 1979; U.S. Pat. No. 4,159,643, issued to Fred E. Watkins on July 3, 1979; U.S. Pat. No. 4,286,661, issued on Sept. 1, 1981 to Imre I. Gazda; U.S. Pat. No. 4,373,583, issued Feb. 15, 1983 to Fleming A. Waters; U.S. Pat. No. Re. 31,313 issued July 19,1983 to John V. Fredd and Phillip S. Sizer, on reissue of their original U.S. Pat. No. 4,274,485 which issued on June 23, 1981; and U.S. Pat. No. 4,278,130, issued July 14, 1981 to Robert T. Evans, et al, all disclose test tools which may be run on a wire line or cable and used to open and close a well at a downhole location by pulling up or slacking off on the wire line or cable by which these test tools are lowered into the well. In each of the above cases, a receptacle device is first run on a wire line and anchored in a landing nipple, then a probe-like device is run and latched into the receptacle.
U.S. Pat. No. 4,134,452 provides only a tiny flow passage therethrough openable and closable by tensioning and relaxing the conductor cable for equalizing pressures across the tool.
U.S. Pat. No. 4,149,593 is an improvement over the device of U.S. Pat. No. 4,134,452 and provides a much greater flow capacity as well as a locking sub which locks the tool in the receptacle with a tenacity somewhat proportional to the differential pressure acting thereacross.
U.S. Pat. No. 4,286,661 is a division of U.S. Pat. No. 4,149,593, just discussed, and discloses an equalizing valve for equalizing pressures across the device disclosed in U.S. Pat. No. 4,149,593.
U.S. Pat. No. 4,159,643 discloses a device similar to those mentioned above and has a relatively small flow capacity. This tool has lateral inlet ports which are closed by tensioning the conductor cable.
U.S. Pat. No. 4,373,583 discloses a test tool similar to those just discussed. It carries a self-contained recording pressure gage suspended from its lower end and therefore sends no well data to the surface during the testing of a well. This tool, therefore, may be run on a conventional wire line rather than a conductor line, since it requires no electrical energy for its operation.
U.S. Pat. No. Re. 31,313 discloses a device similar to that of U.S. Pat. No. 4,373,583 in tnat it has lateral inlet ports which are opened and closed by moving a probe up or down through tensioning or relaxing the wire line or cable on which it is lowered into the well.
The MUST Drill Stem Test Tool of Flopetrol-Johnston disclosed in the brochure mentioned above and in the article published in WORLD OIL magazine provides a non-retrievable valve opened and closed from the surface by tensioning and relaxing the conductor cable connected to the probe-like tool latched into the valve. Even with the valve open and the well producing, no flow takes place through the probe. All flow moves outward through the side of the valve into a bypass passage which then empties back into the tubing at a location near but somewhat below the upper end of the probe. The device provides large or "unrestricted" flow capacity. The probe automatically releases when a predetermined number (up to twelve) of open-close cycles have been performed.
U.S. Pat. No. 4,426,882 which issued to Neal G. Skinner on Jan. 24, 1984 discloses a similar test tool which senses downhole conditions and sends electrical signals to the surface, but the valve for permitting or preventing fluid flow therethrough is not controlled by tensioning and relaxing the cable by which the tool is lowered into the well but is controlled from the surface by electrical means controlling a downhole valve actuator which includes a solenoid.
U.S. Pat. No. 2,673,614, issued to I. A. Miller on Mar. 30, 1954; U.S. Pat. 3,208,531, issued to J. W. Tamplen on Sept. 28, 1965; U.S. Pat. No. 4,043,392, issued to Imre I. Gazda on Aug. 23, 1977; and U.S. Pat. No. 3,472,070, issued to D. V. Chenoweth on Oct. 14, 1969 disclose means for locking well tools in a well flow conductor.
U.S. Pat. No. 2,673,614 shows keys having one abrupt shoulder engageable with a corresponding abrupt shoulder in a well for locating or stopping a locking device in a well at the desired location in a landing receptacle for its locking dogs to be expanded into a lock recess of the receptacle. A selective system is disclosed wherein a series of similar but slightly different receptacles are placed in a tubing string. A locking device is then provided with a selected set of locator keys to cause the device to stop at the preselected receptacle.
U.S. Pat. No. 3,208,531 discloses a locking device which uses keys profiled similarly to the keys of U.S. Pat. No. 2,673,614 but performing both locating and locking functions.
U.S. Pat. No. 4,043,392 discloses a locking device and a selective locating system therefor. This sytem utilizes a profiled key only for locating the device, as was done in the case of U.S. Pat. No. 2,673,614. The various keys vary slightly in profile, but each key and landing receptacle in the system provides two oppositely facing abrupt stop shoulders.
U.S. Pat. No. 3,419,075 issued to Norman F. Brown on Dec. 31, 1968 discloses apparatus having key means with an abrupt stop shoulder engageable with a corresponding stop shoulder in the well flow conduit, and means for retracting the keys to disengage them from such stop shoulder to enable the tool to be moved therepast in the well.
U.S. Pat. No. 3,472,070 discloses a locking device having separate pivoted locking dogs, one looking up and the other looking down, engaged between a pair of upwardly and downwardly facing abrupt shoulders to lock the device against upward or downward displacement. Such locking device and the landing receptacle therefor are more clearly shown in the Composite Catalog of Oil Field Equipment and Services, 1970-71 Edition, pages 506 and 507.
U.S. Pat. No. 4,420,044, issued to William H. Pullin et al on Dec. 13, 1983, discloses a continuous zig-zag control slot and pin arrangement for controlling longitudinal movement of one member relative to another member telescoped thereinto.
The present invention overcomes many of the problems encountered in prior art devices by providing desirable features such as larger flow capacities, positive locking and improved releasing, simpler construction, improved reliability, decreased foulability, and reduced costs.